James Comey, the former FBI director, and Jeff Sessions, the US attorney general, have both been interviewed by the Russian election meddling investigation, it emerged yesterday.

Mr Comey answered questions from the team of Robert Mueller, the special counsel, before Christmas, while Mr Sessions was interviewed last week.

Attorney General Jeff Sessions. Photo: Joshua Roberts/Reuters

The pair are both central to one of Mr Trump's most controversial decisions in office - the firing of Mr Comey, who at the time headed up the Russia investigation.

Critics have questioned whether the move amounts to obstruction of justice, one of the grounds for the impeachment of a president.

Mr Sessions is the first member of Mr Trump's cabinet to be interviewed by the Mueller investigation.

Mr Comey was reportedly asked about memos on Mr Trump's behaviour he wrote before his departure.

One said that Mr Trump asked him to end the FBI investigation into Michael Flynn, the former national security adviser. This is disputed by the president.

Mr Sessions was involved in a number of events believed to be of interest to Mr Mueller, including discussions about the firing of Mr Comey.

After criticism of his contacts with Russians early last year, Mr Sessions recused himself from the investigation - meaning he has no control over Mr Mueller's work.

Mr Sessions, the former Alabama senator, was one of Mr Trump's most vocal supporters in his presidential campaign and played a central role advising on foreign policy.

Since taking office his relationship has soured with Mr Trump after he stepped away from any involvement in the Mueller investigation, despite the president opposing the move.

Mr Sessions is the latest key figure of the Trump team to be interviewed by Mr Mueller, who appears to be nearing the end of his investigation. Steve Bannon, Mr Trump's former campaign manager, has agreed to be questioned, while Hope Hicks, the White House communications director, and Mr Trump himself reportedly are wanted for interview.

The investigation is looking at all Russian election meddling - including the alleged hacking of Democratic Party emails and social media advertising as well as how the Trump campaign behaved.

In a separate development, it was reported that Christopher Wray, the current FBI director, threatened to resign over demands for personnel changes from Mr Sessions and Mr Trump.

Three sources with "direct knowledge" said Mr Wray had threatened to quit if Mr McCabe was removed, according to Axios.

Mr Comey appeared to respond to the news in a tweet: "Good to read reports of people standing up for what they believe in. 'The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy' - MLK."

Meanwhile, US Vice President Mike Pence said yesterday the timing of a long-awaited US Middle East peace initiative depended on the return of Palestinians to negotiations.

Mr Trump's advisers have been working on the outlines of a plan for some time. But Palestinians ruled out Washington as a peace broker after the US president's December 6 recognition of Jerusalem as Israel's capital.

"The White House has been working with our partners in the region to see if we can develop a framework for peace," Mr Pence said in an interview in Jerusalem on the last leg of a three-day Middle East trip.

"It all just depends now on when the Palestinians are going to come back to the table."

Mr Trump's Jerusalem move angered the Palestinians, sparked protests in the Middle East and raised concern among Western countries that it could further destabilise the region. Palestinians see East Jerusalem as capital of a future state.